Utilization of Different Basal Diets for Molt Induction in a Strain of Commercial Laying Hens

Abstract

The objective of the study was to evaluate a nonfasting method for induced molting of laying hens by using different basal diets. An experiment was conducted using 300 H&N Brown hens (aged 95 wk ) randomly assigned to one of five treatment groups: group 1 (NC), which served as the non-molt control group, was provided with a layer ration and exposed to a 16:8 daylight:dark (L:D) photoperiod daily throughout the study, whereas groups 2 (BR), 3 (RB), 4 (C) and 5 (CM) were subjected to an induced molting program. Hens in the BR group were fully fed with a broken rice molt diet, whereas for 14 days, hens in the RB, C and CM groups received rice bran, corn mash and cassava mash molt diets, respectively. During the 2 wk molt period, all birds were exposed to an 8L:16D photoperiod and had access to drinking water at all times. Following the molting period, all hens were fed the layer ration and provided with 16 h of light per day, and production performance was measured for 20 wk. The CM treatment resulted in total cessation of egg production within 7 d. Egg production of hens in the BR, RB and C treatments all decreased to 3.7, 2.6 and 8.7%, respectively. Bodyweight loss ranged from 6.0 to 22.0%, with the highest value for the CM treatment. At the end of the molt period, no significant differences in the mortality rate, the ratio of heterophil to lymphocyte numbers and plasma cortisol concentrations were found among the experimental bird groups. No consistent differences were observed among the molt treatments throughout the 20 wk postmolt period for egg production, egg weight or egg quality. However, the peak of egg production of hens in the CM treatment reached a level of 70% of hen-day egg production, which was higher than those of the other treatments. In addition, during the early phase of the postmolt period, egg production and albumen quality of the CM treatment were significantly improved as compared to those of the control group. At week 2 of the postmolt period, the egg shell thickness of the CM treatment was significantly lower than that of the control group. The results indicated that feeding the cassava molt diet is an effective non-feed removal method for molting laying hens. However, the technique needs to be adjusted to improve egg production and egg shell quality.